1. Field of the Invention
This invention relates to emergency vehicle sirens. It specifically relates to electronic sirens which are operated by actuating a circuit which can provide certain frequencies to an amplifier which then amplifies and broadcasts siren sounds through a speaker. Accompanying the siren is a control circuit and panel generally mounted within the emergency vehicle for selecting certain siren tones and placing the siren in various operational modes.
2. Prior Art
The prior art with regard to electronic circuits for sirens incorporates such sirens as those that were originally only of a wail tone. As sophisticated siren requirements developed, sirens were created that provided not only a wail tone but also a yelp tone and a hi-lo tone. These respective tones are known and appreciated by emergency vehicle operators and have been substantially met with acceptance by the general public as a warning of an approaching emergency vehicle.
The general structure of emergency vehicle sirens comprise a switch panel or circuit mounted within the emergency vehicle. The switch panel and circuit mounted in the emergency vehicle oftentimes was placed under the dashboard of an emergency vehicle. The output of the circuit which provided the tonal nature of the sound was received by a power amplifier which in turn was connected to a speaker for emanating the siren sound.
Oftentimes, it was desirous to have a siren sound of a particular nature such as wail, yelp or hi-lo emanate from the siren by manual control. On the other hand, sometimes an automatic control was implemented of the particular siren sound. All of these controls could be handled by selector switches mounted on the control panel. The selector switches have developed over the years with various circuitry functions to provide various outputs and control functions.
One particular selector function has allowed a tone to emanate from the siren such as a police vehicle until the vehicle is stopped and the transmission is placed in park or neutral. At this point, the siren sound ceases while the officer or driver of the emergency vehicle attends to business with a particular party whom he has apprised by the siren tone.
Upon re-entering the vehicle, the officer or individual driving the emergency vehicle has put the vehicle from neutral or park into a position for driving at which time the siren again emanates its tone. This has caused surprise at the least and extreme annoyance and impromptu responses from the driver of the emergency vehicle or the party being warned such that an accident or other discomfiture could take place.
This particular invention allows for an elimination of the problem of a siren sound emanating when the emergency vehicle is placed in a drive mode from the neutral or park mode. This is due to the switch function which turned off the siren sound not reactivating the siren sound. The overall development of this particular siren elimination or disabling function upon positioning of the shift lever into drive or park enhances emergency vehicle activity as well as the related siren functions as will be seen hereinafter.